Appropriate jam etiquette should ALWAYS be observed. If you’re a novice, stay in the background & play quietly until you get the hang of it. No one is impressed by a newcomer (or old timer) who insists on playing over everyone else’s vocals and instrumental breaks. Rules of etiquette tend to differ from jam to jam and especially between old time (OT) and bluegrass (BG) jams. See below for more on this topic.
Common Sins at a Bluegrass Jam
Perhaps the worst sin is playing out of tune. If you don't have an electronic tuner, buy one. Those little clip-on tuners may be the greatest boon to jamming since the invention of the capo. But a tuner is only good if you use it.
Failure to maintain rhythm is another cardinal sin. Keep your eyes open and watch the right hand of the steadiest rhythm player. Do not get so into what you're doing on your own fret board that you fail to notice that you're completely out of time with the rest of the group. Losing the rhythm is not a cardinal sin. The cardinal sin is when you lose the rhythm and remain unaware of that fact. Use BOTH your ears and eyes to check that you're in rhythm. Tapping your foot can be a useful aid to keeping time but be aware of what you're doing. On a dirt or concrete surface you can tsp or stomp as hard as you like. However , on a wooden floor your foot stomping can set the entire floor to vibrating & become an extreme annoyance to those around you. In this, as with many other things, be aware of what you're doing and how others are being affected.
Noodling on your instrument between tunes: Between songs, many pickers are trying to tune their instruments and your noodling is just plain annoying. If your noodling is your attempt to practice something, move away from the main group and practice in a corner. If your noodling is an attempt to show everyone how good you are, rest assured it is unnecessary. A few well chosen fill-in licks will make point equally well. If noodling is your way of covertly suggesting the next tune, you are better off taking the direct approach and overtly suggesting the tune. If your noodling is just a nervous habit, cut it out! For some reason, banjoists and Dobroists seem to be most guilty of the sin of noodling. I'm not certain why that is but I've noticed that when I lay aside my fiddle and pick up my banjo, I find myself starting to noodle between tunes. Strange but true.
Over-playing: Do not try to play over others. When someone else is taking a solo break or singing the lyrics, playing over them is simply rude. No one has ever garnered any ill will by playing too softly or too little. The worst that will happen in such a case is that the others in the group will chastise you for playing too softly and tell you to play more or more loudly. That will make you feel good. But if the group members have to tell you to back off, you're likely to be insulted. This is unfortunate because it reduces the likelihood that you will return to that jam. But if that does happen, just say "oops, sorry." i.e., Repent and sin no more. Remember that the role of a jammer is try to make the GROUP sound better. The jammer's role is NOT to play louder than the person next to him or to show off! The time to play loudly and to show off is during your solo break. If you want to practice your break before it's turn to solo, do so quietly When it's your turn, step up and play with authority. A good rule of thumb is that if your back up playing and solo playing are at the same volume, you are doing one of two things wrong. i.e., you are either you are playing your back up too loudly or you're not playing your solo loudly enough.
Do not borrow another person's instrument without their permission. This applies most often to bass fiddles. If you see a bass sitting there without a player, it is NOT an open invitation for anyone to pick it up. As I said, this transgression is most common with basses but I've seen people do this with guitars & fiddles as well. It is considered to be very bad form unless you have the owner's permission.
Why Won't They Give Me a Solo Break?
The key to successful jamming (and to most group playing) is to maintain eye contact with whoever is leading that particular song. This is usually, but not always, the vocalist. In the case of instrumentals it is typically the person who kicked off the tune. I see lots of novices wondering why no one gives them a solo break. There are usually three reasons. 1) The leader tried to give you a break but you were too busy looking at your fingerboard. (Dobro players are notoriously guilty of this particular sin.) Failure to make eye contact with the leader at the proper time may be taken to mean that you do not want a break of your own. Ideally, make eye contact with the leader. If you want a break, just nod "yes." If you don't want a break, just shake your head "no." 2) The leader didn’t feel you needed a solo break since you’d already (effectively) taken your "solo" break(s) albeit while the vocalist was singing or the mandolin was trying to be heard for his solo break. 3) The final reason you may not get a break is that the jam leader(s) are being insensitive boors. Sometimes this is a momentary lapse and sometimes it is a persistent personality flaw but don’t jump to conclusions too quickly. I have heard people say "that jam doesn’t like new comers" when I know for a fact that is not true. Give a jam a couple of tries before deciding that the participants are simply too inbred and unsympathetic to deal with.
Diverse Musical Cultures
Rules of etiquette tend to differ from jam to jam and especially between old time (OT) and bluegrass (BG) jams. In BG jams, all pickers are expected to vamp or chop or play back up licks behind the vocalist or whichever instrument is given the nod to take a solo break. In OT and Celtic jams, it’s common for all banjos, mandolins & fiddles to play the melody in unison. There are no solo breaks and improvisation may be frowned upon to a greater or lesser degree. This behavior would quickly make you persona non grata at a BG jam. OT jams typically frown on banjo players with finger picks (and possibly resonators) because such instruments overpower the more traditional-style pickers. Playing Scruggs style banjo at an OT jams is liable to get you ridden out of town on a (f)rail. (Sorry, I couldn't resist.)
Some "folky" jams are not jams at all (at least by my definition) but "open circles" where participants take turns singing and playing. It always pays to stay in the background for a half hour or so until you can deduce the rules. BG jams will often welcome an OT banjo player and even offer him/her solo breaks but you must obey BG etiquette and not keep frailing, etc. over other people’s vocals & breaks. There is also a jam form know as the "slow jam." These are jams for novices who are often intimidated by the breakneck speed of many (but not all) bluegrass jams. Slow jams allow the novice to get his/her feet wet in a non-threatening, mutually supportive environment. My advice is for the novice to attend both types. Even if, in the faster jam, you only chunk quietly in the background, you'll learn to hear the chord changes. That helps to train your ear and might give you the confidence to "push the envelope."
Some jams are led by one or a few people, usually the vocalists. If you want to lead a tune you have two options: 1) wait until the leader asks if you want to lead a tune or 2) ask the leader(s) if you may lead one. Either strategy is OK. Other jams are more democratic. There is no obvious jam leader and the participants are all expected to lead a tune. The custom is for the lead to rotate around the circle. When your turn arrives you can lead a tune or just pass the honor.
Choice of Tunes and Keys
If you are a newcomer to a jam, try to avoid tunes that others are unlikely to know, particularly those with complex chord patterns or odd (i.e.," crooked") timing. This is particularly good advice for non-guitarists. If you’re playing guitar, you’re likely playing full chords that others can hear and also "read the chords" by watching your fingers (assuming that you avoid too many barre chords). But if you’re a non-guitarist, it’s unlikely that others can read your fingerboard so keep it relatively simple. My general rule of thumb is that it's best to avoid a tune if there's no guitar player in the jam who knows that tune. (An exception is when you are playing with skilled jammers. In that situation you can introduce a new, relatively simple tune and expect that everyone will pick it up quickly. If you are going to try a new or more complex tune, tell everyone before you start what the odd chords will be or where the odd timing might come.
In bluegrass, if the song has a vocal, it is the vocalist who calls the key and it can/should be the key in which the vocalist will sing it best. That being said, you should try to avoid keys that are rarely, if ever, used in bluegrass. It may not matter to folks with frets & capos but to (all but the very best) fiddlers, a song done in G#, D#, Db, etc., is just cruel. The most common major keys in BG are C, D, E. F. G, A, &, sometimes Bb B. The most common minor keys are Cm, Dm, Em, Gm, & Am.
In both OT & Celtic jams most instrumental tunes are done in one key & one key only. This is also true of instrumentals at BG jams, particularly when playing traditional fiddle tunes. (e.g., Soldier's Joy is virtually always played in Dmaj) but in some bluegrass tunes (e.g., breakdowns) there's a little more leeway and a tune might be played in one of two keys. e.g., Remington Ride is usually played in G but I've occasionally heard it played in Amajd A (but never in any other key).
As indicated above, in BG jams, the vocalist typically calls the key and the key can (and will) change from tune to tune. In OT & Celtic jams, however, the group will usually play a series of songs in the same key. Then they'll do a series of tunes in a different key. This is because OT banjos (and possibly fiddles) often change the tunings of their instruments for different keys. To avoid the delays caused by having to shift from e.g., G tuning to D tuning, they tend to play 5-10 "G tunes" and then play 5-10 "D tunes", etc.
Advice for Beginners
Too often, newbies will make the mistake of sitting (or standing) outside the jam circle. They are, understandably shy and unsure of themselves. But a far better idea is to sit right up front, ideally, next to someone who's willing to whisper the chords to you. At the very least, sit in a spot where you can see the fingers of a guitarist who knows the tunes. You can then (visually) follow the chord changes until you start to hear those changes. The worst thing you can do as a novice is to sit in the back where a) you can't hear the vocals and/or the melody clearly or b) see the fingers of other pickers. Your musical life gets a lot easier if you can shift from chord to chord without looking at your fingers and your fret board. Your eyes should be watching the fingers & fret board of the other players. Jamming is an interactive, social pursuit. If you're not attending to what your jam mates are doing, your ignoring a lot of useful information. A good jammer doesn't necessarily need to know the song to play it. He/she just needs to be able to hear (and even anticipate) the chord changes and immediately play those chords
A Final Note
As a final plea to the "regulars" in ongoing jam sessions: Make a point of welcoming newcomers. They are the future of the music we all love. And to the newcomers: don't be so thin-skinned that you take every suggestion as criticism. The person might just be trying to help you!
For another excellent discussion of the basics of bluegrass jamming, see the article by Tom Barnwell of the Southeastern Bluegrass Association at
http://users.ece.gatech.edu/~tom/roles.html.
Mill Creek Boys (aka the Mill Creek Persons) at the Pocono Bluegrass Festival